Multi Effect Evaporator commonly uses sensible heat in the condensate to preheat liquor to be flashed. In this unit high TDS reject water is heated and circulated to increase the salt concentration. It is very expensive to operate as it requires steam for working so we pass only 2-3% of effluent to MEE.
It Is used to evaporate the residue water from MEE concentrated liquid and generate dry salt for dispose. MEE concentrated liquid have large amount of water content which is not possible to dispose so salt dryer is used after MEE to reduce water content from MEE concentrated liquid.
It is a special application membrane unit with suitable process molecular weight cutoff (MWCO) for purification of brine solution and removal of other residual impurities. In first stage specific type of NF membranes are used for recovery of brine from RO reject. We get pure brine solution with total hardness <50 and TDS value of 10 gpl. In second stage high recovery sea water membranes are used to concentrate the brine solution and recovered brine water is used up to 120 gpl for recycling purpose. Third stage is for polishing of concentrated brine solution and removal of residual hardness from it.
The pure brine solution obtained is then converted into solid form i.e. used back in the process with the help of cooling crystallizer.
Cooling crystallizer is a system that has excellent thermodynamic efficiency with high performance & Low maintenance.